1. Field of the Invention
This invention relates to an optical communication module, which converts an electrical signal into an optical signal and outputs it, or converts an optical signal into an electrical signal and outputs it.
2. Description of the Related Art
In optical communications, multichannel transmission is being used with increasing communication speed. An optical communication module for the multichannel transmission uses an optical element array which comprises easy-to-array surface emitting elements such as VCSELs (Vertical Cavity Surface Emitting LASERs) or the like or surface receiving elements such as photodiodes or the like, arranged in array. The optical element array is placed on a supporting member (a substrate) comprising a crystalline material such as a metal material, a ceramic material, silicon, or the like.
In the optical communication module, optical fibers to optically connect to the optical element array are typically disposed parallel to a surface of the supporting member, so that routing thereof is facilitated. Accordingly, an optical member (also referred to as “lens block” or “optical block”) is used in order to optically couple together the optical element array, from which light enters or exits perpendicular to the surface of the supporting member, and the optical fibers, from which light enters or exits parallel to the surface of the supporting member.
For example, in JP-A-2004-246279, an optical member having condensing lenses and an optical path bending reflective surface is disposed between an optical element array and optical fibers in which optical paths lie in a 90 degree direction to the optical element array. The optical member, which is made of resin or glass, is generally used.
Now, when assembling the optical communication module, it is necessary to align the optical member and the optical element array.
A known method to align the optical member and the optical element array is to operate the optical element array then determine a location of the optical member while observing light intensity transmitted to the optical fibers. However, this aligning method has been very time-consuming due to requiring electrical wiring, operation of the optical element array and measurement. It has been questionable from the point of view of mass production.
A known method to more conveniently align the optical member and the optical element array is to mechanically align them without operating the optical element array.
JP-A-2006-65358 proposes an aligning method by providing guide pins in a supporting member of an optical element array, while providing holes in an optical member and using the supporting member of the optical element array as a supporting member for the optical member as well.
Refer to JP-A-2004-246279 and JP-A-2006-65358, for example.